Homeowners are becoming more conscious about the appearance of the garage area. In addition to finished walls and storage locations, another area of desired improvement is the floor of the garage. Rather than just accepting a bare concrete surface, homeowners are looking for a strong, durable, stylish finish. This is often attained by staining, painting, or sealing the garage floor.
The concrete floor should first be prepared prior to applying a finishing treatment. Often, the treatment is applied after at least several years of use of the concrete floor. The years of use have resulted in the accumulation of dirt, grease, and stains of various kinds. Preferably, these accumulations will be removed, and the concrete prepared, before the concrete surface is ready for the finishing treatment.
A variety of materials have been used to clean and prepare concrete surfaces. Cleaning solutions are available and have been used in attempts to clean the concrete surface before painting or coating. Cleaners that have been used include water, liquid detergents, and solvents such as paint thinners and alcohols. Cleaning a concrete surface includes removing dirt, grime, grease, and oils from the surface. Therefore, combinations of cleaners can be employed in stages. For example, the approach might be to first wash the surface using detergent and water, followed by a second wash using a specialty cleaner and concentrating on the grease and oil spots.
Fully preparing a concrete surface for finishing requires more than just cleaning. The surface of concrete may be rather hard and smooth, and often does not provide the roughness necessary for a paint or coating to adhere properly. The surface should first be roughened in order to provide a suitable surface for adhesion. The surface may be roughened using physical or chemical roughening treatments. Physical treatments to prepare a concrete surface include sandblasting and shot blasting, both of which use abrasive materials forced through a nozzle under pressure to physically abrade the concrete surface. This physical abrasion provides a surface enabling a coating with good adhesion properties. However, the physical process also has several drawbacks. The process requires significant equipment, usually including a large air compressor, hoses, and nozzle assembly. It is often difficult to contain and thoroughly clean up the abrasive material used. The process can be lengthy and physically difficult. It is often noisy, dusty, and uncomfortable when sandblasting or shot blasting. Lastly, physical abrasion requires experience to provide a consistent and even physical wearing, as well as the proper degree of roughening.
Alternatively, the concrete surface may be chemically roughened, in a process called etching. Etching dissolves acid-sensitive calcareous components of concrete from the surface through an acid reaction. The most common acid sensitive components in concrete include calcium carbonate, calcium oxide, and calcium hydroxide. The calcareous components interact with acidic components to form water, carbon dioxide, and calcium salts. The calcium salts will usually be somewhat soluble in the water present in the acid solution used. The dissolving of calcareous components roughens the concrete surface.
Generally, muriatic acid (hydrogen chloride) has been used to etch concrete surfaces. As a strong acid, it generally etches the concrete surface rapidly. Though muriatic acid is effective at etching, there are several associated drawbacks with its use. Muriatic acid is highly corrosive to other surfaces, especially metal, because it is such a strong acid. It causes almost instant staining or rust of such surfaces. Muriatic acid is also highly corrosive to eyes and skin, is toxic, and causes burning of mucous membranes. Additionally, the salts formed from the reaction can be very damaging to concrete if they are not removed from the surface.